1. Field of the Invention
The present invention relates to a package for a semiconductor device, and more particularly, to a package for a MOSFET device in a chip scale package that provides superior thermal performance and very low package resistance, as well as methods of manufacturing thereof.
2. Description of the Prior Art
Semiconductor devices, especially MOSFET devices, generally desire very low package resistance (RDSon) with good thermal performance. It is also generally desirable to have the package as small as possible with reference to the die. Thus, numerous packaging concepts and methods have been developed in the prior art.
The present invention provides a semiconductor device that includes a lead frame including a source pad, at least two source lead rails at a periphery of the source pad, a gate pad adjacent to the source pad, and a gate lead rail at a periphery of the gate pad. A die is coupled to the source pad and the gate pads such that a surface of the die opposite the pads is substantially flush or co-planar with the ends of the lead rails. A stiffener is coupled to the lead frame and electrically isolated therefrom.
In accordance with one aspect of the present invention, the stiffener comprises a copper slug.
In accordance with another aspect of the present invention, the stiffener is coupled to the lead frame with polyamide tape that provides the electrical isolation.
In accordance with a further aspect of the present invention, the lead frame includes at least three source lead rails.
Thus, the present invention provides a chip scale package for semiconductor devices that has very low package resistance (RDSon) and superior thermal performance. The package may not fully conform to the chip scale size definition since its package size is 1.65 times its chip size, but this ratio is one of the most aggressive for MOSFET Power devices.
Other features and advantages of the present invention will be understood upon reading and understanding the detailed description of the preferred exemplary embodiments found herein below, in conjunction with reference to the drawings, in which like numerals represent like elements.